Buy a house for my family

$1 Billion? Building up a house with a big garden.

I'd check where the money came from and if it's a mistake (which would be logical) and then I'd transfer it back.

Invest it so I can get more money

I would give my mother a lot of the money so that she no longer has to work and can live her life. Put on one part well so that it multiplies and with the other part fulfills my wishes.

ich würde mir ein gutes auto kaufen. ich bin die ganze zeit dran, was zu suchen, was mir gefällt und passt und da ist oft der preis das hindernis. e-autos zb. sind sehr viel teurer als ihr benzin-bruder.

Go for a walk to ring on the door of my dream house and make the old man a good offer

Buy a car

Pay all my Bills , get a child, buy a house

Buy property and build a house